People opening or running shops and facilities, managers checking whether they need indoor hydrants, and designers of buildings
When does a building need indoor hydrants? 14 facilities checked
Indoor hydrants are needed from 500, 700 or 1,000 m² of total floor area by use, doubled or tripled if fire-resistant. Of 14 facilities an AI checked, a hotel of 2,251.44 m² is over even 2,100 m².
The flow
You
Your AI
Laydyne
You1Ask whether a building needs indoor hydrantsBy its use, total floor area and construction.
Laydyne2Check each facility's hydrantsThe threshold, doubled or tripled by the structure (Fire Service Act Order, Article 11).check_space→ The banquet hall of 1,262.06 m² needs them even if fire-resistant, but not with flame-retardant finishes too.
Laydyne3Measure the reach to the farthest pointEvery part within 25 m of a hose connection.edit_spacecheck_spaceget_view_image→ One hydrant: 50.93 m; four: 19.46 m.
Whether a building needs indoor hydrants is set by Article 11 of the Order for Enforcement of the Fire Service Act (the Fire Service Act Order), from its use (Appended Table 1 of the Order), its total floor area and how it is built. Here are 14 facilities an AI checked in earlier articles, with the tool it calls over MCP (the indoor hydrant check of check_space).
1. The rules
Use (item of Appended Table 1)
Needed
(1) theatres, assembly halls, wedding venues and the like
From 500 m² of total floor area (Article 11(1)(i))
From 700 m² of total floor area (Article 11(1)(ii))
(11) shrines and temples; (15) offices and the like
From 1,000 m² of total floor area (Article 11(1)(iii))
A basement, a "windowless floor" (one without enough openings for firefighting), or floor 4 and above (the ground floor being floor 1)
From 100 m² of floor area for (1), 150 m² for (2)–(10), (12) and (14), and 200 m² for (11) and (15) (Article 11(1)(vi))
The structure raises the threshold (Article 11(2)). It is tripled if the main structure is fire-resistant and the finishes of the walls and ceilings are flame-retardant; doubled if the building is only fire-resistant, or quasi-fire-resistant with flame-retardant finishes.
Hospitals (item (6)(a)(1) and (2)), care homes (item (6)(b)) and the other buildings of Article 12(1)(i) (the sprinkler rule) go no higher, even doubled or tripled, than 1,000 m² plus the floor area of the parts that the Regulation for Enforcement of the Fire Service Act (the Fire Service Act Regulation) specifies.
2. From 500 m² for item (1)
Facility (use)
Total floor area
Construction
Threshold
Indoor hydrants
A banquet hall for 200 (item (1)(b))
1,262.06 m²
Other
500 m²
Needed
A banquet hall for 200 (item (1)(b))
1,262.06 m²
Fire-resistant
1,000 m²
Needed
A banquet hall for 200 (item (1)(b))
1,262.06 m²
Fire-resistant, flame-retardant finishes
1,500 m²
Not needed
A community centre (item (1)(b))
420.08 m²
Any
500 m²
Not needed
3. From 700 m² for restaurants, shops, hotels, flats, hospitals, schools, factories and warehouses
Facility (use)
Total floor area
Construction
Threshold
Indoor hydrants
An izakaya (item (3)(b))
165.24 m²
Any
700 m²
Not needed
An exhibition hall (item (4))
920.56 m²
Other
700 m²
Needed
An exhibition hall (item (4))
920.56 m²
Fire-resistant
1,400 m²
Not needed
An exhibition hall (item (4))
920.56 m²
Quasi-fire-resistant, flame-retardant finishes
1,400 m²
Not needed
A supermarket (item (4))
5,909.48 m²
Other
700 m²
Needed
A supermarket (item (4))
5,909.48 m²
Fire-resistant, flame-retardant finishes
2,100 m²
Needed
A business hotel (item (5)(a))
2,251.44 m²
Other
700 m²
Needed
A business hotel (item (5)(a))
2,251.44 m²
Fire-resistant
1,400 m²
Needed
A business hotel (item (5)(a))
2,251.44 m²
Fire-resistant, flame-retardant finishes
2,100 m²
Needed
A block of flats (item (5)(b))
1,641.45 m²
Other
700 m²
Needed
A block of flats (item (5)(b))
1,641.45 m²
Fire-resistant
1,400 m²
Needed
A block of flats (item (5)(b))
1,641.45 m²
Fire-resistant, flame-retardant finishes
2,100 m²
Not needed
A hospital (item (6)(a)(1) and (2))
6,524.8 m²
Fire-resistant, flame-retardant finishes
1,000 m²
Needed
A day nursery (item (6)(c))
530.44 m²
Any
700 m²
Not needed
A primary school's wing (item (7))
2,058.6 m²
Other
700 m²
Needed
A primary school's wing (item (7))
2,058.6 m²
Fire-resistant
1,400 m²
Needed
A primary school's wing (item (7))
2,058.6 m²
Fire-resistant, flame-retardant finishes
2,100 m²
Not needed
A steel warehouse (item (14))
1,484.04 m²
Other
700 m²
Needed
A steel warehouse (item (14))
1,484.04 m²
Quasi-fire-resistant, flame-retardant finishes
1,400 m²
Needed
A steel warehouse (item (14))
1,484.04 m²
Fire-resistant, flame-retardant finishes
2,100 m²
Not needed
A machine shop (item (12)(a))
343.64 m²
Any
700 m²
Not needed
Over the threshold even when tripled. The supermarket (5,909.48 m²) and the hotel (2,251.44 m²) are over 2,100 m² even if fire-resistant with flame-retardant finishes, so they need them. The school's wing (2,058.6 m²) is 41.4 m² short of 2,100 m² and needs none.
A hospital's threshold is not tripled. The hospital of 6,524.8 m², fire-resistant with flame-retardant finishes, still has a threshold of 1,000 m² (assuming none of the parts the Regulation specifies), so it needs them.
4. From 1,000 m² for offices and the like
Facility (use)
Total floor area
Construction
Threshold
Indoor hydrants
A 24-hour gym (item (15))
327.24 m²
Any
1,000 m²
Not needed
A three-storey office building (item (15))
923.52 m²
Any
1,000 m²
Not needed
5. A floor that needs them below the threshold (Article 11(1)(vi))
Facility (use)
Floor
Floor area
Threshold
Indoor hydrants
A machine shop (item (12)(a))
Windowless
343.64 m²
150 m²
Needed
The machine shop has a total floor area of 343.64 m², under 700 m². But if its shutter cannot be opened from outside and so does not count as an opening, its floor is windowless; with 150 m² or more of floor area, it needs them.
6. Where: within 25 m of a hose connection
The steel warehouse
From the farthest point of the floor
Within 25 m
One hydrant by the office
50.93 m
No
Four hydrants
19.46 m
Yes
Factories and warehouses (items (12)(a) and (14)) take class 1 hydrants, with every part of each floor within 25 m, measured in a straight line, of a hose connection. Other uses take class 1 or wide-range class 2 hydrants (25 m), or class 2 hydrants (15 m) (Article 11(3)(i) and (ii)).
Four hydrants with their 25 m reach, and 19.46 m from the floor's farthest point
Does this building (a single-storey warehouse with a total floor area of 1,500 m², quasi-fire-resistant with flame-retardant finishes, as drawn) need indoor hydrants? If so, how many, and where, so that every part of the floor is within 25 m?
9. What this does not check
Article 11(1)(iv) (item (16-2)), Article 11(1)(v) (designated combustibles), and leaving hydrants out where sprinklers or the like are fitted (Article 11(4)) are not covered.
The total floor areas are measured to the centres of the walls. In the end, ask the local fire department.
